Just little stuff:
Extended Cards work better in the long run than a boosted card until you obtain time dilation and celestial opposition to boost the duration.
If you have a party member that is putting in the deeps a lot more than the others. It's sometimes best to focus extended/boosted balances on them alone.
AST can't aoe before the 50's. It's best to spread your balance card and place Combust II + I dots on many mobs as you can while you weave in spells.
Bole can be used to lessen the requirement to heal your tank. Giving you more time to do other things.
Disable should always be used on a tank buster skill. You may also use it on a boss charging an aoe.
Light speed is your bread and butter when it comes to quick dpsing and massive aoe heal spams. The mana cost reduction will prevent you from dying out on mana. And if you get the trait to reduce the damage penalty. Eventually you can use Gravity to help clear mobs or Malefic 2's on the run.
When you obtain Celestial opposition, you can use this skill offensively (to prevent mobs from touching your tank for a while) and increase all the buffs you not only casted on your party members but yourself. (Mana Recovery, Light speed, Synastry) *Personally I use this a lot with Light speed and Synastry to burst aoe heal when it calls for it.
For tips on cards:
Monks and Ninjas typically love the Arrow over Balance. But sometimes It's a good idea to use on a BLM if the fight is starting to get mobile.
Everyone else loves the Balance for obvious reasons.
Extended Ewer on Bard while they sing foes requiem is not a bad idea. You get a longer magic debuff effect.
Extended Spire has its uses on dragoons and Bards that spam aoes.
The spear is kind of useless imo, I only see it for one use and that's to reduce a tanks GCD. (If its a boosted Spear, it does make a huge difference)
Collective Unconscious:
Aside from the damage reduction effect, I actually love to use this skill to stack regens on a big pull. You'll be amazed in how much healing would be covered if you used synastry + this + Aspected Helios (Regen Stance) + Aspected Benefict (Regen stance) time dilation + celestial opposition.
AST is a fun class. And while people do complain that the class has some potency nearing WHM's. It's only because we don't have a Fairy to heal for us. (I can't imagine being able to heal heavy damage with just benefict I) And because of that fact and the way the class works, it requires a lot of focus and thinking to execute this class pretty well.